Substrate treating apparatus

ABSTRACT

Disclosed is a substrate treating apparatus for performing a predetermined treatment on a substrate. The apparatus includes: a spin table configured to be rotatable around a vertical axis; a rotational driving device having a grounded rotary shaft connected to a center portion of the spin table and configured to rotate the spin table in a horizontal plane; a holding mechanism having a plurality of support pins, provided on a top face of the spin table adjacent to an outer circumference and made of a conductive material, and configured to hold a substrate in a horizontal posture while the substrate is spaced apart from the top face of the spin table; and a ground line having conductivity, constituting a part of the spin table, and electrically connecting the plurality of support pins and the rotary shaft.

BACKGROUND OF THE INVENTION (1) Field of the Invention

The present invention relates to a substrate treating apparatus for performing a predetermined treatment on a substrate, such as a semiconductor wafer, a substrate for a liquid crystal display or for an organic electroluminescence (EL) display, a glass substrate for photomask, an optical disk substrate, a magnetic disk substrate, a ceramic substrate, a substrate for a solar cell, or the like (hereinafter, simply referred to as substrate) while rotating the substrate supported on a spin table.

(2) Description of the Related Art

Examples of currently-used apparatus of this type includes one including a spin table and a plurality of support pins. See, for example, Japanese Unexamined Patent Application Publication No. 2017-228582 (FIG. 4). In this apparatus, a substrate is supported with the plurality of support pins, and a rear face thereof is spaced apart from a top face of the spin table. A front face of the substrate undergoes a predetermined treatment while the substrate is rotated by the spin table. When the substrate is originally charged or a treatment liquid supplied to the substrate is charged, particles may be attached to the substrate by electrostatic force caused by the charging. Accordingly, electric charge of the substrate is to be removed.

In the currently-used apparatus, a part of the support pin is formed with a conductive material, and the support pin is grounded by conduction to a rotary shaft. As a result, the supported substrate is grounded via the support pin and the rotary shaft, achieving removal of electric charge in the substrate.

However, the conventional example with such constructions has the following problems. Specifically, in the currently-used apparatus, conduction has to be made between a plurality of support pins adjacent to an outer circumference of the spin table in plan view and a rotary shaft arranged at the center of the spin table in plan view. In order to achieve this, conduction between the support pins and the rotary shaft can be achieved, for example, by forming the spin table with a conductive material.

On the other hand, since the spin table also has to be chemical resistant, a material available for the substrate treating apparatus is limited. In prior art, examples of the material include one obtained by mixing carbon with a fluororesin-based resin. However, a drawback of a significantly increasing cost arises when the spin table is formed with such a material as above.

SUMMARY OF THE INVENTION

The present invention has been made regarding the state of the art noted above, and its one object is to provide a substrate treating apparatus that allows a suppressed cost while preventing charging in a substrate with a devised construction for conduction.

The present invention is constituted as stated below to achieve the above objects.

(1) A first aspect of the present invention provides a substrate treating apparatus that performs a predetermined treatment on a substrate. The apparatus includes: a spin table configured to be rotatable around a vertical axis; a rotational driving device having a grounded rotary shaft connected to a center portion of the spin table and configured to rotate the spin table in a horizontal plane; a holding mechanism having a plurality of support pins, provided on a top face of the spin table adjacent to an outer circumference and made of a conductive material, and configured to hold a substrate in a horizontal posture while the substrate is spaced apart from the top face of the spin table; and a ground line having conductivity, constituting a part of the spin table, and electrically connecting the plurality of support pins and the rotary shaft.

According to the aspect of the present invention, the ground line constituting a part of the spin table, whose center portion is connected to the grounded rotary shaft, electrically connects the plurality of support pins and the rotary shaft. This can achieve more suppression in cost while preventing the charging in the substrate than a configuration for conduction with the entire spin table.

(2) It is preferred in the aspect of the present invention that the plurality of support pins is each formed with a material in which a polyetheretherketone (PEEK) material contains carbon nanotubes.

The PEEK material as a fluorine-based resin can provide chemical resistance. The PEEK material containing carbon nanotubes achieves conductivity. Thus, the ground line can be configured suitably.

(3) It is preferred in the aspect of the present invention that the ground line is a plate member that is thinned toward a surface of the spin table.

Since the ground line is configured by a plate member thinned toward the surface of the spin table, it is possible to hardly receive resistance of wind during rotation of the spin table. This can achieve suppressed adverse effect of turbulence on the treatment.

(4) It is preferred in the aspect of the present invention that the plurality of support pins is at least four in number, and the ground line forms a cross shape in plan view, and is connected to four of the plurality of support pins.

Since the cross shape is easy to form, the ground line can be configured easily. Moreover, four portions are grounded, leading to sufficient removal of charges in the substrate.

(5) It is preferred in the aspect of the present invention that the ground line is attached to a lower face of the spin table.

This can prevent the treatment liquid for treating substrates from flowing around. Moreover, even if the treatment liquid flows around, it can easily drop. Therefore, it is possible to suppress the inconvenience caused by adhesion of the treatment liquid accompanying the treatment.

(6) It is preferred in the aspect of the present invention that the ground line is embedded into the lower face of the spin table.

Since the ground line is embedded, less unevenness on the lower face of the spin table is obtainable. This can suppress turbulence accompanying rotation of the spin table.

(7) It is preferred in the aspect of the present invention that the spin table includes a groove formed therein with a major axis from each of the support pins to the rotary shaft individually, the groove has a trapezoidal shape whose upper side is formed longer than a lower side thereof in a longitudinal cross section along a minor axis orthogonal to the major axis, and the ground line has a longitudinal cross section along the minor axis that corresponds to the groove.

The ground line can be attached to the spin table through the groove without using a physical force by a screw or the like. Accordingly, it is possible to prevent a phenomenon (called creep phenomenon), which may be likely to occur in resin or the like, that the resin deforms with time due to load application.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there are shown in the drawings several forms which are presently preferred, it being understood, however, that the invention is not limited to the precise arrangement and instrumentalities shown.

FIG. 1 illustrates an overall configuration of a substrate treating apparatus according to one embodiment of the present invention.

FIG. 2A is a plan view of an overall spin table, and FIG. 2B is a partially enlarged view thereof.

FIG. 3A is a bottom view of the overall spin table, and FIG. 3B is a partially enlarged view thereof.

FIG. 4 is a longitudinal sectional view of a stationary pin.

FIG. 5 is a sectional view on arrow 101-101 in FIGS. 4 and 6.

FIG. 6 is a longitudinal sectional view of a movable pin.

FIG. 7 is a perspective view of the movable pin seen from below.

FIG. 8 is a plan view of a switching mechanism.

FIG. 9 is a positional relationship of magnets in a holding position of the movable pin.

FIG. 10 is a positional relationship of magnets in a delivery position of the movable pin.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following describes one embodiment of the present invention with reference to drawings.

FIG. 1 illustrates an overall configuration of a substrate treating apparatus according to one embodiment of the present invention. FIG. 2A is a plan view of an overall spin table, and FIG. 2B is a partially enlarged view thereof. FIG. 3A is a bottom view of the overall spin table, and FIG. 3B is a partially enlarged view thereof.

The substrate treating apparatus according to the embodiment is a single-wafer processing apparatus for treating substrates W one by one. The substrate treating apparatus includes a base unit 1, a chuck unit 3, a scattering prevention cup 5, a supply nozzle 7, and a controller 9.

The base unit 1 rotates the chuck unit 3, and releases holding of a substrate W held by the chuck unit 3. The chuck unit 3 rotates while holding the substrate W in a horizontal posture. The scattering prevention cup 5 prevents scattering of a treatment liquid, supplied from the supply nozzle 7 to the substrate W, to the surrounding. The scattering prevention cup 5 moves vertically between a treatment level (denoted by solid lines in FIG. 1) and a delivering level (denoted by chain double-dashed lines in FIG. 1), that is below the treatment level.

The base unit 1 includes an electric motor 11 and a switching mechanism 13. The electric motor 11 and the switching mechanism 13 are located inside of a cover 15 having chemical resistance. In other words, the cover 15 covers the electric motor 11 and the switching mechanism 13. Since the electric motor 11 and the switching mechanism 13 are located inside of the cover 15, there is no need that the electric motor 11 and the switching mechanism 13 are treated to be resistant to a treatment liquid or formed with a material resistant to a treatment liquid. Therefore, cost reduction of the base unit 1 is obtainable.

The electric motor 11 includes a rotary shaft 17 in a vertical direction. The rotary shaft 17 rotates around a shaft axis P1 along the vertical direction. The rotary shaft 17 is made of a conductive metallic material. The rotary shaft 17 is electrically connected to a grounding conductor, not shown, for conduction. The electric motor 11 outputs a rotation position of the rotary shaft 17 from an encoder 19. The rotary shaft 17 is supported by a bearing 21 so as to be rotatable, and extends upward from the cover 15. The chuck unit 3 is attached to an upper part of the rotary shaft 17.

The electric motor 11 described above corresponds to the “rotational driving device” in the present invention.

The chuck unit 3 includes a spin table 23 and a holding mechanism 25. The spin table 23 is circular in plan view as shown in FIG. 2A. The spin table 23 is formed by a material resistant to a treatment liquid supplied from the supply nozzle 7, for example. Specifically, a fluororesin is cited as the material. More specifically, polyether ether ketone (PEEK) is cited.

The holding mechanism 25 includes two stationary pins 27 and two movable pins 29, for example. The spin table 23 has through holes 31 positioned so as to correspond to the two stationary pins 27 and the two movable pins 29. The through holes 31 each penetrate from a top face to a lower face of the spin table 23. The two stationary pins 27 and the two movable pins 29 are inserted into the through holes 31 individually. The spin table 23 has notches 33 formed around the through holes 31 individually. The notches 33 are formed lower in level than the top face of the spin table 23. The notches 33 each have a U-shape in plan view.

The notches 33 allow easy discharge of the treatment liquid laterally. Consequently, the treatment liquid flowing laterally from the top face of the spin table 23 can be prevented from stagnating at portions where the stationary pins 27 and the movable pins 29 are attached. This can prevent generation of particles caused by the stagnated treatment liquid.

Here, the stationary pin 27 and the movable pin 37 described above correspond to the “support pin” in the present invention.

Reference is now made to FIG. 4. FIG. 4 is a longitudinal sectional view of the stationary pin.

The stationary pin 27 includes a bottom pin section 35 and a top pin section 37. The bottom pin section 35 is provided below the spin table 23. The bottom pin section 35 is coupled to the top pin section 37 via the through hole 31. The bottom pin section 35 includes a pin supporting portion 35 a, a fixing screw 35 b, a balance weight 35 c, a lid member 35 d, and a fixing seal 35 e. The fixing screw 35 b for fixing the top pin section 37 to the pin supporting portion 35 a is screwed into an upper part of the pin supporting portion 35 a. The balance weight 35 c is attached to a lower part of the fixing screw 35 b. The balance weight 35 c balances the weight with the movable pin 29. The lid member 35 d is attached to a lower part of the balance weight 35 c. The lid member 35 d fixes the balance weight 35 c to the supporting portion 35 a. The lid member 35 d is fixed to the supporting portion 35 a via the fixing seal 35 e. The top pin section 37 is attached to the upper part of the pin supporting portion 35 a via a fixing seal 35 f. The fixing seal 35 f prevents the treatment liquid from entering the inside to corrode the fixing screw 35 b, and the like.

The top pin section 37 includes a shaft 37 a and a support piece 37 b. The support piece 37 b includes a projection 37 c. The shaft 37 a is fixed to the supporting portion 35 a via the fixing screw 35 b while being placed on the fixing seal 35 f. The support piece 37 b has a substantially ellipse shape in plan view. The support piece 37 b supports a substrate W by contacting a back face adjacent to an outer circumference and an outer periphery edge of the substrate W. The support piece 37 b has a slope face 37 d adjacent to the shaft axis P1. The slope face has a slope gradually increasing in level from the shaft axis P1 toward an outer circumference of the spin table 23. The slope face 37 d contacts the rear face of the substrate W. The projection 37 c is formed on the support piece 37 b closer to the outer circumference of the spin table 23 than the fixing screw 35 b in plan view. The projection 37 c contacts the outer periphery edge of the substrate W to restrict outward movement of the substrate W. The stationary pin 27 is attached such that an ellipse longitudinal axis of the support piece 37 b is brought into a posture along the outer periphery edge of the spin table 23.

In the stationary pin 27, a shim 39 can be inserted into a contact portion between the top pin section 37 and the top face of the pin supporting portion 35 a. The shim 39 is a thin stainless steel plate. Replacing the shim 39 by one having a different thickness or increasing or decreasing the number of shims 39 can adjust a level of the top pin section 37 from the top face of the spin table 23 in the stationary pin 27. Accordingly, the level where the substrate W is supported is adjustable, and thus the substrate W is adjustable to be horizontal. The fixing seals 35 e and 35 f are each an elastic member having chemical resistance. Specifically, the fixing seals 35 e and 35 f are preferably made from a fluororubber (vinylidene fluoride (FKM), tetrafluoroethylene-propylene (FEPM), tetrafluoroethylene-perfluorovinyl ether (FFKM) or the like), for example.

As shown in FIG. 3A, the bottom pin section 35 of the stationary pin 27 is screwed on the lower face of the spin table 23 via a cover 41. Note that the pin cover 41 is not shown in FIG. 4 for the convenience of illustration. The pin supporting portion 35 a and the support piece 37 b as components of the stationary pin 27 described above are preferably formed by a conductive material having chemical resistance. More preferably, the material is a conductive PEEK material (PEEK-CNT) containing carbon nanotubes. This ensures conductivity.

Ground lines 43 are provided on the lower face of the spin table 23. The ground lines 43 partially form the spin table 23. Specifically, as shown in FIGS. 2A and 3A, four ground lines 43 are located so as to conduct the two stationary pins 27 and the two movable pins 29. The ground line 43 has conductivity. Preferably, the material is a conductive PEEK material (PEEK-CNT) containing carbon nanotubes. The ground line 43 has a first end, adjacent to the circumference, that is attached to conduct the pin supporting portion 35 a. The ground line 43 has a second end, adjacent to the shaft axis P1, that is attached to conduct the rotary shaft 17. The rotary shaft 17 is connected to a grounding conductor via the electric motor 11.

The ground line 43 is formed with the PEEK material as a fluorine-based resin, and thus can provide chemical resistance. The PEEK material containing carbon nanotubes achieves conductivity. Thus, the PEEK-CNT can form the ground line 43 suitably.

Reference is now made to FIG. 5. FIG. 5 is a sectional view on arrow 101-101 in FIGS. 4 and 6.

The spin table 23 has a groove 45 formed on the lower face thereof so as to have a cross shape in plan view. The groove 45 has an inverted trapezoidal shape in its longitudinal cross section. The groove 45 has the major axis from the stationary pin 27 or the movable pin 29 toward the rotary shaft 17. The groove 45 has a trapezoidal shape whose upper side is formed longer than a lower side thereof in a longitudinal cross section along a minor axis orthogonal to the major axis. The groove 45 has a depth in a direction corresponding to a leg of the trapezoid that is smaller than the major axis of the groove 45. The ground line 43 described above fits in the groove 45. That is, the ground line 43 is embedded into the lower face of the spin table 23. Since the ground line 43 is embedded, less unevenness on the lower face of the spin table 23 is obtainable. This can suppress turbulence accompanying rotation of the spin table 23. Moreover, the ground line 43 is attached to the lower face of the spin table 23. This can prevent the treatment liquid for treating substrates W from flowing around into the ground line 43. Moreover, even if the treatment liquid flows around, it can easily drop. Therefore, it is possible to suppress the inconvenience for the ground line 43 caused by adhesion of the treatment liquid. Moreover, the ground line 43 is a plate member that is thinned toward a surface of the spin table 23. Accordingly, even if the ground line 43 is not embedded into but is attached to the lower face of the spin table 23, it is possible to hardly receive resistance of wind during rotation of the spin table 23. This can achieve suppressed adverse effect of turbulence on the treatment. The ground line 43 has a longitudinal cross section substantially equal to the shape of the groove 45. In other words, the ground line 43 has a shape whose longitudinal cross section along the minor axis of the groove 45 corresponds to the groove 45. The ground line 43 is formed to have an outer shape slightly smaller than the groove 45. Consequently, the ground line 43 can be attached to the groove 45 by passing the ground line 43 into the groove 45 radially along a surface of the spin table 23 without using a physical force by a screw or the like. This causes the ground line 43 to pass through the groove 45 loosely. Accordingly, it is possible to prevent a phenomenon (called creep phenomenon), which may occur in the resin material, that the resin material deforms with time due to load application. In this way, such an inconvenience that conduct is hard to perform due to deformation of the ground line 43 can be prevented.

When the spin table 23 is made of a non-conductive material such as PEEK, attached particles may be difficult to detach due to electrostatic charge. This may cause the substrate W to be contaminated with particles. In the present embodiment, arrangement of the ground lines 43 causes grounding of the stationary pins 27 described above and the movable pins 29 to be mentioned below. Accordingly, electrostatic charge can be prevented, and thus the inconvenience described above can be prevented. In addition, the conductive PEEK material containing carbon nanotubes is very expensive. However, in the present embodiment, not entirely but only a part of the spin table 23, which part is cross-shaped in plan view, is made of the conductive PEEK material. This can prevent inconvenience described above while suppressing costs.

Reference is now made to FIG. 6. FIG. 6 is a longitudinal sectional view of the movable pin.

The movable pin 29 includes a bottom pin section 47 and a top pin section 49. The bottom pin section 47 is provided below the spin table 23. The bottom pin section 47 is coupled to the top pin section 49 via the through hole 31. The bottom pin section 47 includes a pin supporting portion 47 a, a rotation magnet 47 c, a lid member 47 d, a fixing seal 47 e, a bearing 47 f, a fixing seal 47 g, and a tubular member 47 h.

A fixing screw 47 b for fixing the top pin section 49 to the pin supporting portion 47 a is screwed into an upper part of the pin supporting portion 47 a. The rotation magnet 47 c is attached to a lower part of the fixing screw 47 b. The rotation magnet 47 c is attached to a lower end of the movable pin 29. The rotation magnet 47 c is used for rotating the movable pin 29 by switching the surrounding magnetic poles, which is to be mentioned later. The lid member 47 d is attached to a lower part of the rotation magnet 47 c. The lid member 47 d fixes the rotation magnet 47 c to the pin supporting portion 47 a. The lid member 47 d is fixed to the pin supporting portion 47 a via the fixing seal 47 e. The pin supporting portion 47 a is attached to the through hole 31 by the fixing seal 47 g via the bearing 47 f and the tubular member 47 h. The pin supporting portion 47 a is fixed only to an inner ring of the bearing 47 f, and is not fixed to an outer ring of the bearing 47 f. The outer ring of the bearing 47 f is fixed to the through hole 31. The tubular member 47 h is attached to an upper part of the pin supporting portion 47 a while a lower face thereof is spaced apart from the top face of the pin supporting portion 47 a.

The tubular member 47 h is fixed only to the outer ring of the bearing 47 f and the lower face of the spin table 23. The lower face of the tubular member 47 h is spaced apart from the pin supporting portion 47 a. The bearing 47 f does not include a seal member between the inner ring and the outer ring thereof. Accordingly, fluid can pass between the inner ring and the outer ring of the bearing 47 f. The bearing 47 f is made of a material that is resistant to a treatment liquid. For example, the bearing 47 f preferably has the inner ring and the outer ring made of a conductive resin. The bearing 47 f is preferably made of, for example, a conductive PEEK material containing carbon nanotubes. Moreover, a rolling element of the bearing 47 f is preferably made of silicon carbide (SiC) in view of securing abrasion resistance and conductivity. The fluid flowing on the bearing 47 f downward is discharged to the surroundings through a flow path 47 i in a gap between the lower face of the tubular member 47 h and the pin supporting portion 47 a. Consequently, in combination with the effect of the notches 33, the stagnation of the treatment liquid at a root of the movable pin 29 on the spin table 23 can be more effectively prevented.

The top pin section 49 includes a shaft 49 a and a support piece 49 b. The support piece 49 b includes a projection 49 c. The shaft 49 a is fixed to the supporting portion 47 a via the fixing screw 47 b while being placed on the fixing seal 47 g. The support piece 47 b has a substantially ellipse shape in plan view. The support piece 47 b supports a substrate W by contacting a back face adjacent to the outer circumference and an outer periphery edge of the substrate W. The support piece 47 b has a slope face 49 d adjacent to the shaft axis P1. The slope face 49 d has a slope gradually increasing in level from the shaft axis P1 toward the outer circumference of the spin table 23. The slope face 49 d contacts a rear face of the substrate W. The projection 49 c is formed on the support piece 49 b closer to the outer circumference of the spin table 23 than the fixing screw 47 b in plan view. The projection 49 c contacts the outer periphery edge of the substrate W to restrict outward movement of the substrate W. Here, similarly to the stationary pin 27, the movable pin 29 can cause a shim 51 to be inserted into a contact portion between the top pin section 49 and the top face of the pin supporting portion 47 a. Replacing the shim 51 by one having a different thickness or increasing or decreasing the number of shims 51 can adjust a level of the top pin section 49 from the top face of the spin table 23 in the movable pin 29. This yields adjustment of a surface level of the substrate W. This is also called camming adjustment. The material of the fixing seals 47 e and 47 g is preferably the same as that of the fixing seals 35 e and 35 f described above. The movable pin 29 is configured so as to be rotatable around a shaft axis P2 by the bearing 47 f.

As shown in FIGS. 3A and 3B, the bottom pin section 47 of the movable pin 29 is screwed and fixed to the lower face of the spin table 23 via a carrier plate 53. Note that the carrier plate 53 is not shown for the convenience of illustration in FIG. 6. Among the components constituting the movable pin 29 described above, the bottom pin section 47 and the top pin section 37 are preferably made of a conductive material having chemical resistance. More preferably, the material is a conductive PEEK material (PEEK-CNT) containing carbon nanotubes. This ensures conductivity.

The movable pin 29 is attached such that an ellipse longitudinal axis of the support piece 49 b is brought into a posture along the outer periphery edge of the spin table 23 when the movable pin 29 rotates into the holding position, which is similar to the stationary pin 27. Consequently, the movable pin 29 rotates into the holding position, whereby the longitudinal axes of the support pieces 37 b and 49 b are each brought into a posture along the outer periphery edge of the spin table 23. Consequently, air resistance in the support pieces 37 b and 49 b when the spin table 23 rotates can be reduced, and turbulence of air flow around the stationary pin 27 and the movable pin 29 can be suppressed. This results in suppression of uneven treatment around the peripheral edge of the substrate W adjacent to the stationary pin 27 and the movable pin 29.

The ground line 43 shown in FIGS. 2A and 3 has a first end, adjacent to the outer circumference, that is attached to conduct the bottom pin section 47. The ground line 43 has a second end, adjacent to the shaft axis P1, that is attached to conduct the rotary shaft 17.

Reference is now made to FIGS. 3 and 7. FIG. 7 is a perspective view of the movable pin seen from below.

The carrier plate 53 includes a first end 53 a, a second end 53 b, an attachment part 53 c, a round screw hole 53 d, and a long threaded screw hole 53 e. The carrier plate 53 is made of a material that is resistant to a treatment liquid. The material is preferably a fluororesin. The material is more preferably PEEK.

The first end 53 a is a part of the carrier plate 53 along an arc corresponding to the outer periphery edge of the spin table 23. The second end 53 b is a part, opposite to the first end 53 a, of the arc corresponding to the outer periphery edge of the spin table 23. The attachment part 53 c is a part where the movable pin 29 formed adjacent to the first end 53 a is attached. The round screw hole 53 d is an attachment hole formed adjacent to the second end 53 b and configured to perform screwing and fixation to the spin table 23. The long threaded screw hole 53 e is an attachment hole formed adjacent to the first end 53 a and configured to perform screwing to the spin table 23. The hole is a long hole having a longitudinal axis in the radial direction of the spin table 23.

The carrier plate 53 includes the long threaded screw hole 53 e as described above. Accordingly, the first end 53 a is moved in the radial direction of the spin table 23 while a screw in the long threaded screw hole 53 e is released, whereby the position of the movable pin 29 in the radial direction of the spin table 23 can be adjusted. This can easily perform adjustment such that the substrate W can be held suitably in the radial direction of the spin table 23. In other words, easy adjustment can be performed to eliminate so-called “core blurring” such that the rotation center of the spin table 23 matches the center of the substrate W. This results in enhanced in-plane uniformity of the treatment in the substrate W.

The carrier plate 53 has a housing unit 55 formed at a position adjacent to the attachment part 53 c. The housing unit 55 are formed on the lower face of the spin table 23 and laterally of the rotation magnet 47 c. The housing unit 55 houses a stationary magnet 57. The stationary magnet 57 constantly applies a magnetic field to the rotation magnet 47 c. The rotation magnet 47 c to which the stationary magnet 57 applies the magnetic field rotates by being attracted to the fixed magnet 57 by a magnetic force, and is stationary in a stable state. Accordingly, the movable pin 29 rotates around the axis P2 to be stationary. This position corresponds to the holding position. As shown by solid lines in FIG. 2B, the holding position is a position where the projection 49 c contacts an edge of the substrate W. On the other hand, the delivery position is a position where the movable pin 29 is rotated around the shaft axis P2, the projection 49 c is separated from the edge of the substrate W, and a peripheral edge of a rear face of the substrate W is supported in contact with the slope face 49 d, as shown by chain double-dashed lines in FIG. 2B. Consequently, when the movable pin 29 is in the delivery position, the substrate W can be delivered by a transfer arm not shown. Since the stationary magnet 57 is arranged laterally of the rotation magnet 47 c, the degree of rotation when the movable pin 29 is rotated into the holding position can be easily adjusted by the position of the stationary magnet 57.

The stationary magnet 57 and the rotation magnet 47 c described above are located concyclically around the rotation center P1 of the spin table 23 in plan view, as shown in FIGS. 3A and 3B. With such arrangement, the stationary magnet 57 and the rotation magnet 47 c are both visible from the outer circumference as shown in FIG. 7. This achieves easy operation during maintenance.

Reference is now made to FIG. 1 as well as FIGS. 8 to 10. FIG. 8 is a plan view of the switching mechanism. FIG. 9 is a positional relationship of magnets in the holding position of the movable pin. FIG. 10 is a positional relationship of magnets in the delivery position of the movable pin.

The switching mechanism 13 includes an air cylinder 59, a support arm 61, and drive magnets 63. The air cylinder 59 includes an operating shaft 65 expanding and contracting in the vertical direction. The support arm 61 is attached to the operating shaft 65. The support arm 61 has a length over the two movable pins 29. The drive magnets 63 are attached to both ends of the support arm 61 individually. The drive magnets 63 are each located closer to the inner circumference of the spin table 23 than the rotation magnet 47 c in plan view. In other words, the drive magnets 63 are each located closer to the shaft axis P1 of the spin table 23 than the rotation magnet 47 c and the stationary magnet 57. The drive magnet 63 generates a stronger magnetic force than that by the stationary magnet 57.

The switching mechanism 13 causes the operating shaft 65 of the air cylinder 59 to contract such that the drive magnet 63 is brought into a lowered position, shown by solid lines in FIG. 1, at the holding position where the substrate W is held. Such a state is caused at a position in a normal state, for example, when the power supply is cut off due to any power failure or power supply trouble. Here, the state has a positional relationship in plan view as shown in FIG. 9. That is, a magnetic force only by the stationary magnet 57 is applied to the rotation magnet 47 c of the movable pin 29, and the rotation magnet 47 c and the stationary magnet 57 are attracted to each other by the magnetic force, whereby the movable pin 29 is rotated into the holding position.

On the other hand, the switching mechanism 13 causes the operating shaft 65 of the air cylinder 59 to expand such that the drive magnet 63 is brought into a raised position, shown by chain double-dashed lines in FIG. 1, at the delivery position where the substrate W is released. Here, the state has a positional relationship in plan view as shown in FIG. 10. That is, a stronger magnetic force than that applied to the rotation magnet 47 c of the movable pin 29 by the stationary magnet 57 is applied from the drive magnet 63 to the rotation magnet 47 c. Then, the rotation magnet 47 c is attracted to the drive magnet 63, whereby the movable pin 29 are rotated into the delivery position.

It is preferred that the rotation magnet 47 c, the stationary magnet 57, and the drive magnet 63 described above are each a neodymium magnet. The neodymium magnet is a rare-earth magnet containing neodymium, iron, and boron as main components. The neodymium magnet generates a strong magnetic field.

The switching mechanism 13 is located closer to the shaft axis P1 of the spin table 23 than the rotation magnet 47 c and the stationary magnet 57 in plan view. Consequently, the drive magnet 63 can be located adjacent to the shaft axis P1 of the spin table 23. This can achieve reduction in size of the switching mechanism 13.

The controller 9 is formed by a CPU and a memory, and the like. The controller 9 controls supply of a treatment liquid from the supply nozzle 7 or swing of the supply nozzle 7 between a standby position and a supply position. The standby position corresponds to a position where an ejection port of the supply nozzle 7 is above the shaft axis P1 as shown in FIG. 1. The standby position is a position where the ejection port of the supply nozzle 7 is laterally apart from the scattering prevention cup 5. The controller 9 controls upward and downward movement, i.e., between a treatment level and a delivering level of the scattering prevention cup 5. The controller 9 controls rotation of the electric motor 11. For example, the controller 9 performs control to increase a rotational speed at a predetermined acceleration toward a treatment speed, and to maintain the treatment speed over a treatment period of time when reaching the treatment speed. After the treatment period of time elapses, the controller 9 performs control to decrease a rotational speed at a predetermined negative acceleration to stop rotation. The controller 9 receives a signal from an encoder 19. The controller 9 refers to an output from the encoder 19 when stopping the electric motor 11. The controller 9 stops the electric motor 11 to have the positional relationship shown in FIG. 8. Specifically, rotation of the electric motor 11 is controlled such that rotation magnets 47 c of the two movable pins 29 and the drive magnet 63 of the switching mechanism 13 face each other in the radial direction of the spin table 23. The controller 9 controls upward and downward movement of the drive magnet 63 by the switching mechanism 13.

The substrate treating apparatus having the above-described construction performs treatment on the substrate W as under, for example. Here, the controller 9 does not operate the switching mechanism 13 normally. That is, the drive magnet 63 is located at the lowered position shown by solid lines in FIG. 1. In such a normal situation, the rotation magnet 47 c is attracted and rotated by a magnetic force of the stationary magnet 57 as shown in FIG. 9. Accordingly, the movable pin 29 is located at the holding position indicated by solid lines in FIG. 2B.

The controller 9 moves the scatter preventive cup to the delivering level, and also operates the switching mechanism 13 to move the drive magnet 63 to the raised position. The raised position is indicated by chain double-dashed lines in FIG. 1. Then, as shown in FIG. 10, the rotation magnet 47 c is attracted to the drive magnet 63. Accordingly, the movable pin 29 is moved to the delivery position indicated by chain double-dashed line in FIG. 2B.

The controller 9 moves a transfer arm (not shown), holding the substrate W to be treated, above the spin table 23, and lowers the transfer arm to place the substrate W on the slope face 37 d of the stationary pin 27 and the slope face 49 d of the movable pin 29.

After the transfer arm moves outward, the controller 9 performs control to move the scatter preventive cup upward to the treatment level. The controller 9 operates the switching mechanism 13 to move the drive magnet 63 downward to the lowered position indicated by solid lines in FIG. 1. Then, as shown in FIG. 9, the rotation magnet 47 c releases its attraction by the drive magnet 63. Accordingly, the rotation magnet 47 c is attracted and rotated by the magnetic force of the stationary magnet 57. This causes the movable pin 29 to be moved to the holding position indicated by solid lines in FIG. 2B.

The controller 9 operates the supply nozzle 7 so as to swing the supply nozzle 7 from the standby position to the supply position. Then, the controller 9 causes the supply nozzle 7 to supply a treatment liquid to the substrate W for a treatment period of time while the electric motor 11 rotates at a treatment speed.

After a predetermined period of time elapses, the substrate W is unloaded by reverse operation of a series of the operation described above.

According to the aspect of the present embodiment, the switching mechanism 13 applies no magnetic field of the drive magnet 63 to the rotation magnet 47 c normally, and applies a magnetic field of the drive magnet 63 to the rotation magnet 47 c to rotate the movable pins 29 individually to the delivery position only when the substrate W is delivered. Consequently, the movable pins 29 are individually rotated into the holding position normally by the magnetic force from the stationary magnet 57. On the other hand, the movable pins 29 are individually rotated into the delivery position by the magnetic force from the drive magnet 63 of the switching mechanism 13 only when the substrate W is delivered. As a result, a spring, a cam plate, a lifting plate, and the like are not necessary, achieving reduction in weight of the spin table with a simple construction. Moreover, along with the reduction in weight of the spin table 23, the spin table 23 can be removed easily when maintenance is performed to replace the two stationary pins 27 and the two movable pins 29 that need to be replaced periodically. Accordingly, the burden on an operator at the time of the maintenance can also decrease.

Moreover, with the aspect of the present embodiment, the two stationary pins 27 and the two movable pins 29 are electrically connected to the rotary shaft 17 through the ground line partially forming the spin table 23. This can achieve more suppression in cost while preventing the charging in the substrate W than a configuration for conduction with the entire spin table 23.

The present invention is not limited to the foregoing examples, but may be modified as follows.

(1) In the embodiment described above, the rotation magnet 47 c and the stationary magnet 57 are located concyclically around the shaft axis P1. However, the present invention is not limitative to this configuration. In other words, the rotation magnet 47 c and the stationary magnet 57 may be located in the radial direction of the spin table 23.

(2) In the embodiment described above, the stationary magnet 57 is located laterally of the rotation magnet 47 c. However, the present invention is not limitative to this configuration. That is, it is only necessary for the stationary magnet 57 to rotate the movable pin 29 into the holding position by applying a magnetic field to the rotation magnet 47 c. Accordingly, the position where the stationary magnet 57 is arranged is not limited.

(3) In the embodiment described above, the switching mechanism 13 is formed by the air cylinder 59. However, the present invention is not limitative to this configuration. That is, the drive magnet 63 may have any construction as long as the drive magnet 63 is movable between a position adjacent to the rotation magnet 47 c and a position apart from the rotation magnet 47 c.

(4) In the embodiment described above, the spin table 23 includes the notches 33. However, such a construction is not essential in the present invention.

(5) In the embodiment described above, the carrier plate 53 can cause the movable pins 29 to adjust a position in the radial direction of the spin table 23. However, such a construction is not essential to the present invention. This construction may be omitted for cost suppression if so-called core blurring does not significantly affect the treatment.

(6) In the embodiment described above, the stationary pins 27, the movable pins 29, and the support pieces 37 b and 49 b each have an ellipse shape in plan view. However, the present invention is not limitative to this configuration. For example, the support pieces 37 b and 49 b may have a circular shape in plan view.

(7) In the embodiment described above, the two stationary pins 27 and the two movable pins 29 are provided in the chuck unit 3. However, the number is not limited in the present invention.

(8) In the embodiment described above, the substrate treating apparatus is exemplified that is configured to perform treatment by supplying a treatment liquid through the supply nozzle 7. However, the present invention is applicable to any substrate treating apparatus that performs a predetermined treatment while rotating a substrate W.

(9) In the embodiment described above, the stationary pin 27 and the movable pin 29 are made of PEEK-CNT. However, the present invention is not limitative to these. That is, other materials may be used as long as they are chemically resistant and electrically conductive.

(10) In the embodiment described above, the ground line 43 is configured to form a cross shape in plan view. However, the present invention is not limitative to this configuration. For example, when the total number of the movable pins 27 and the stationary pins 29 is six, they may be formed in a shape of six lines in plan view. However, even in this case, it is not prevented that only four of the six pins are electrically connected to the cross-shaped ground line 43.

(11) In the embodiment described above, the ground line 43 is provided on the lower face of the spin table 23. However, the present invention is not limitative to this construction. That is, the ground line 43 may be provided on the top face of the spin table 23. In addition, the ground line 43 is inserted into and attached to the groove 45. However, the ground line 43 may be attached by screwing or the like when there is no influence of creep phenomenon.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention. 

What is claimed is:
 1. A substrate treating apparatus for performing a predetermined treatment on a substrate, the apparatus comprising: a spin table configured to be rotatable around a vertical axis; a rotational driving device having a grounded rotary shaft connected to a center portion of the spin table and configured to rotate the spin table in a horizontal plane; a holding mechanism having a plurality of support pins, provided on a top face of the spin table adjacent to an outer circumference and made of a conductive material, and configured to hold a substrate in a horizontal posture while the substrate is spaced apart from the top face of the spin table; and a ground line having conductivity, constituting a part of the spin table, and electrically connecting the plurality of support pins and the rotary shaft.
 2. The apparatus according to claim 1, wherein the plurality of support pins is each formed with a material in which a polyetheretherketone (PEEK) material contains carbon nanotubes.
 3. The apparatus according to claim 1, wherein the ground line is a plate member that is thinned toward a surface of the spin table.
 4. The apparatus according to claim 2, wherein the ground line is a plate member that is thinned toward a surface of the spin table.
 5. The apparatus according to claim 1, wherein the plurality of support pins is at least four in number, and the ground line forms a cross shape in plan view, and is connected to four of the plurality of support pins.
 6. The apparatus according to claim 2, wherein the plurality of support pins is at least four in number, and the ground line forms a cross shape in plan view, and is connected to four of the plurality of support pins.
 7. The apparatus according to claim 3, wherein the plurality of support pins is at least four in number, and the ground line forms a cross shape in plan view, and is connected to four of the plurality of support pins.
 8. The apparatus according to claim 4, wherein the plurality of support pins is at least four in number, and the ground line forms a cross shape in plan view, and is connected to four of the plurality of support pins.
 9. The apparatus according to claim 1, wherein the ground line is attached to a lower face of the spin table.
 10. The apparatus according to claim 2, wherein the ground line is attached to a lower face of the spin table.
 11. The apparatus according to claim 3, wherein the ground line is attached to a lower face of the spin table.
 12. The apparatus according to claim 4, wherein the ground line is attached to a lower face of the spin table.
 13. The apparatus according to claim 5, wherein the ground line is attached to a lower face of the spin table.
 14. The apparatus according to claim 6, wherein the ground line is attached to a lower face of the spin table.
 15. The apparatus according to claim 7, wherein the ground line is attached to a lower face of the spin table.
 16. The apparatus according to claim 8, wherein the ground line is attached to a lower face of the spin table.
 17. The apparatus according to claim 9, wherein the ground line is embedded into the lower face of the spin table.
 18. The apparatus according to claim 10, wherein the ground line is embedded into the lower face of the spin table.
 19. The apparatus according to claim 11, wherein the ground line is embedded into the lower face of the spin table.
 20. The apparatus according to claim 1, wherein the spin table includes a groove formed therein with a major axis from each of the support pins to the rotary shaft individually, the groove has a trapezoidal shape whose upper side is formed longer than a lower side thereof in a longitudinal cross section along a minor axis orthogonal to the major axis, and the ground line has a longitudinal cross section along the minor axis that corresponds to the groove. 